Implement frame attribution (FrameBlamer)

content/renderer/renderer_blink_platform_impl.cc

Index: content/renderer/renderer_blink_platform_impl.cc
diff --git a/content/renderer/renderer_blink_platform_impl.cc b/content/renderer/renderer_blink_platform_impl.cc
index e2d537f0f841c29ecced8e3d6aae036b9bb7934c..690d7ceac6d970c2e2f8bbc7562a30b460443c67 100644
--- a/content/renderer/renderer_blink_platform_impl.cc
+++ b/content/renderer/renderer_blink_platform_impl.cc
@@ -252,7 +252,9 @@ RendererBlinkPlatformImpl::RendererBlinkPlatformImpl(
       default_task_runner_(renderer_scheduler->DefaultTaskRunner()),
       loading_task_runner_(renderer_scheduler->LoadingTaskRunner()),
       web_scrollbar_behavior_(new WebScrollbarBehaviorImpl),
-      renderer_scheduler_(renderer_scheduler) {
+      renderer_scheduler_(renderer_scheduler),
+      web_blame_context_(new WebBlameContextImpl(
+          RenderThreadImpl::current()->blame_context())) {
 #if !defined(OS_ANDROID) && !defined(OS_WIN)
   if (g_sandbox_enabled && sandboxEnabled()) {
     sandbox_support_.reset(new RendererBlinkPlatformImpl::SandboxSupport);
@@ -303,6 +305,12 @@ blink::WebThread* RendererBlinkPlatformImpl::currentThread() {
   return BlinkPlatformImpl::currentThread();
 }
 
+blink::WebBlameContext* RendererBlinkPlatformImpl::threadBlameContext() {
+  if (!main_thread_->isCurrentThread())
+    return nullptr;
+  return web_blame_context_.get();
+}
+
 blink::WebClipboard* RendererBlinkPlatformImpl::clipboard() {
   blink::WebClipboard* clipboard =
       GetContentClient()->renderer()->OverrideWebClipboard();